Objects having cores with nanoparticle binders

Abstract

According to examples, an object may include a shell including a polymer binder and build material powder; and a core at least partially encompassed by the shell, the core including build material powder and a metal nanoparticle binder.

What is claimed is: 
     
       1. A green body, comprising:
 a shell including a polymer binder and build material powder selected from the group consisting of a metal, a metal alloy, and a ceramic; and 
 a core at least partially encompassed by the shell, the core consisting of the build material powder, a nanoparticle binder selected from the group consisting of AIN SiC, Si 3 N 4 , WC, Al 2 O 3 , AI(OH) 3 , Fe 2 O 3 , Fe 3 O 4 , MgO, SiO 2 , TiO 2 , Y 2 O 3 , ZnO ZrO 2 , BaCO 3 , In 2 O 3 , SnO 2 , carbon, magnesium, manganese, aluminum, iron, titanium, niobium, tungsten, chromium, tantalum, cobalt, nickel, vanadium, zirconium, molybdenum, palladium, platinum, copper, silver, gold, cadmium, zinc, and combinations thereof, and one or more of a pigment, a dye, a solvent, a co-solvent, a surfactant, a biocide, an anti-kogation agent, a viscosity modifier, a buffer, and a stabilizer, a nanoparticle binder having a size ranging from about 1 nm to about 100 nm. 
 
     
     
       2. The green body of  claim 1 , wherein the polymer binder is selected from the group consisting of polypropylene, polyethylene, low density polyethylene, high density polyethylene, polyethylene oxide, polyethylene glycol, acrylonitrile butadiene styrene, polystyrene, styrene-acrylonitrile resin, polyphenyl ether, polyamide 11, polyamide 12, polymethyl pentene, polyoxymethylene, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polytetrafluoroethylene, perfluoroalkoxy alkane, polyphenylene sulfide, polyurethane, polyvinyl alcohol, polylactic acid, and polyether ether ketone. 
     
     
       3. The object green body of  claim 1 , wherein the shell has a tensile strength greater than about 1 MPa. 
     
     
       4. The green body of  claim 1 , wherein the core is at least about 50% encompassed by the shell. 
     
     
       5. The green body of  claim 1 , wherein a volume ratio of a loading of the polymer binder in the shell to a loading of the nanoparticle binder in the core ranges from about 250:1 to about 1:20. 
     
     
       6. The green body of  claim 1 , wherein a thickness of the shell ranges from about 1 mm to about 20 mm. 
     
     
       7. The green body of  claim 1 , wherein the shell further includes a metal salt binder. 
     
     
       8. The green body of  claim 1 , wherein the polymer binder is present in an amount of about 1 wt. % in the shell and the nanoparticle binder is present in an amount of about 0.02 wt. % in the core. 
     
     
       9. The green body of  claim 1 , wherein the nanoparticle binder has a size ranging from about 1 nm to about 50 nm. 
     
     
       10. A core of a green body, consisting of:
 a coalesced build material powder selected from the group consisting of a metal, a metal alloy, and a ceramic; 
 a nanoparticle binder intermingled throughout the coalesced build material powder, the nanoparticle binder having a size ranging from about 1 nm to about 100 nm and selected from the group consisting of AIN, SiC, Si 3 N 4 , WC, Al 2 O 3 , Al(OH) 3 , Fe 2 O 3 , Fe 3 O 4 , MgO, SiO 2 , TiO 2 , Y 2 O 3 , ZnO, ZrO 2 , BaCO 3 , In 2 O 3 , SnO 2 , carbon, magnesium, manganese, aluminum, iron, titanium, niobium, tungsten, chromium, tantalum, cobalt, nickel, vanadium, zirconium, molybdenum, palladium, platinum, copper, silver, gold, cadmium, zinc, and combinations thereof; and 
 one or more of a pigment, a dye, a solvent, a co-solvent, a co-solvent, a surfactant, a biocide, an anti-kogation agent, a viscosity modifier, a buffer, and a stabilizer. 
 
     
     
       11. A method comprising:
 spreading a layer of build material powder selected from the group consisting of a metal, a metal alloy, and a ceramic; 
 selectively depositing a polymer binder onto a first select area on the spread layer of the build material powder to form a shell of a green body; 
 selectively depositing a nanoparticle binder having a size ranging from about 1 nm to about 100 nm onto a second select area on the spread layer of build material powder to form a core of the green body consisting of the build powder material, the nanoparticle binder selected from the group consisting of AIN, SiC, Si 3 N 4 , WC, Al 2 O 3 , AI(OH) 3 , Fe 2 O 3 , Fe 3 O 4 , MgO, SiO 2 , TiO 2 , Y 2 O 3 , ZnO ZrO 2 , BaCO 3 , In 2 O 3 , SnO 2 , carbon, magnesium, manganese, aluminum, iron, titanium, niobium, tungsten, chromium, tantalum, cobalt, nickel, vanadium, zirconium, molybdenum, palladium, platinum, copper, silver, gold, cadmium zinc and combinations thereof, and one or more of a pigment, a dye, a solvent, a co-solvent, a surfactant, a biocide, an anti-kogation agent, a viscosity modifier, a buffer, and a stabilizer; 
 applying energy to form a green body from the spread layer of build material powder, the deposited polymer binder, the deposited nanoparticle binder, and the one or more of a pigment, a dye, a solvent, a co-solvent, a surfactant, a biocide, an anti-kogation agent, a viscosity modifier, a buffer, and a stabilizer; and 
 applying energy to the green body to form a brown body. 
 
     
     
       12. The method of  claim 11 , wherein the polymer binder is selectively deposited over a first select area of the spread layer of the build material powder to form the green body leaving a third area of the spread build material powder that does not form the green body. 
     
     
       13. The method of  claim 11 , wherein the step of applying energy to the green body to form the brown body further comprises applying sufficient energy to sinter the build material powder. 
     
     
       14. The method of  claim 11 , wherein the step of applying energy further comprises applying sufficient energy to cause interparticle binding within the core of the green body from the nanoparticle binder and the build material powder.